Studies of cyclic di- tert.-butylsilylene derivatives of diols and hydroxy acids by gas chromatography—mass spectrometry

Abstract

Cyclic di- tert.-butylsilylene (DTBS) derivatives have been introduced recently as protecting groups for 1,2-, 1,3- and 1,4-diols. Analogous cyclic derivatives can also be formed from other bifunctional groupings. In this paper, based on gas chromatography—mass spectrometry, studies are reported of DTBS derivatives of twenty-one 1,2-diols, four 1,3-diols, two catechols, two α-hydroxy acids and one β-hydroxy acid. In general, the derivatives showed very satisfactory gas chromatographic properties, having retention indices (on OV-1 phase) about 150–250 units above those of analogous butaneboronates. The mass spectra showed several characteristic features. Molecular ions were almost always present, though they were in modest abundance except from aromatic substrates. DTBS derivatives of acyclic and alicyclic diols gave major ions corresponding to [M  C 4H 9] + and [M  C 4H 9  C 3H 6] +, whereas catechol derivatives yielded abundant molecular ions and distinctive fragment ions of types [M  C 4H 8] +• and [M  C 4H 8  C 3H 7] +.